The video highlights a few differences between the CASIO fx-115ES PLUS 2nd edition and the CASIO fx-991EX CLASSWIZ.
They are both great calculators for the money (about the same cost in the US). I am not sure why CASIO continues to offer both of them, but there are enough differences that it is worth comparing them before choosing.
My slight preference is for the fx-115ES because of the larger display text, remainder division (mod), GCD/LCM, and a slightly more intuitive CALC/SOVE approach, and a keyboard with marginally better feel. I do wish, though, that it had the faster processor from the fx-991EX.
18 июн 2020